Gun for perforating casing



Dec. 29, 1953 1 G, MGKEAN GUN FOR PERFORATING CASING 2 Sheets-Sheet l Filed sept. 11, 195o JNVENToR. Jerome G. McKean,

I Lvw ATTORNEY Dec. Z, 1953 J. G. MCKEAN GUN FOR PERFORATING CASING 2 Sheets-Sheet 2 Filed sept. 11, 1950 JNVENTOR. J @rome 6. McKean, BY

A TTORNEY.

Patented Dec. 29, 1953 UNITED STT GUN FOR PERFORATING CASING of Delaware Application september 11, 195o, serial No. 184,168

3 Claims.

This invention relates to guns for perforating pipe in oil Wells or the like and more particularly to guns which are small enough to run through tubing in a well for perforating casing beneath the tubing.

Guns and explosives have long been used for perforating casing in cil wells and the art is well developed. As commonly constructed, the barrels of bullet guns used for such purposes are iixed horizontally in a carriage and these barrels approach in length, as far as is practical, the diameter of the casing so as to obtain the maximum re power. Where shaped charges of explosive are used for perforating casing, they also have been mounted in fixed position in a carriage which is nearly as large as the casing in the well so as to locate the charge in the optimum position or stand-off distance from the casing. Even under the best conditions, effective perforation of oil well casing and the cement which usually surrounds it, is dinicult to accomplish, and since the size of the gun or explosive is important, casing perforators have not been run into the well through tubing or other pipe smaller in diameter than the casing.

It has recently been proposed to perform certain operations including the perforating of casing in an oil well while tubing is in it. See for example application of Theodore A. Huber, Serial No. 133,025, led December 15, 1949, for Method of Completing and Repairing Oil Wells where the use of a casing perforating gun capable of being run through tubing is required. Large savings in time and cost can be eiected in this way if effective perforation can be accomplished.

In accordance with application Serial No. 184,161, iiled on even date herewith by Theodore A. Huber, now Patent No. 2,639,770, it is proposed to solve the problem of providing elective iiring power to perforate casing with an assembly which is run into and out ofthe well through tubing by arranging the guns in their carriage on trunnions and by providing means for rotating them from the vertical positions which they occupy while being lowered into the well, into horizontal firing positions. Inasmuch as the guns may be fired by electricity, Huber proposed to employ an electric motor to rotate them exactly the right amount.

In accordance with the present invention, it is proposed to provide a structure which can be run into the well through tubing and which works automatically to swing the barrels of bullet guns or position shaped charges of explosive properly and accomplish the purposes proposed by Huber.

The carriage for the guns is made of two parts, one of which moves, under the influence o1 gravity, to effect the desired movement as it comes out of the tubing. When the guns re, the reactive force causes further relative movement of the two parts of the carriage and brings them into such position that the carriage can be retrieved from the Well through the tubing.

The objects of the invention will be apparent from the following description, taken in connection with the accompanying drawings in which:

Fig. 1 is a vertical cross-sectional View of tubing in an oil well and a cross-sectional View of a bullet gun, constructed in accordance with the present invention, located therein in the running-in position, it being understood that as many barrels as desired may be employed, all being like those illustrated.

Fig. 2 is a vertical cross-sectional view of tubing and casing in an oil well with the gun of Fig. 1 beneath the tubing with the barrels shown in horizontal position and being fired.

Fig. 3 is a vertical cross-sectional view of the tubing and gun of Fig. 1 but showing the position Y of the carriage and barrels after firing and in retrieving position.

Fig. 4 is an enlarged transverse cross-sectional view of the gun of Fig. 1, the view being taken on the line 4 4 of Fig. 1.

Fig. 5 is a side View of one of the barrels of the gun of Figs. 1 to 4, partly cut away and showing the arrangement for holding the barrels in horizontal position and releasing them when they are red so that they can rotate an additional amount.

Fig. 6 is a vertical cross-sectional view of tubing in an oil well and a cross-sectional view of a gun, using shaped charges of explosives and constructed in accordance with the invention, located therein in running-in" position.

Fig. '7 is a vertical cross-sectional View of tubing and casi-ng in an oil well Awith the gun oi Fig. 6 beneath the tubing and with the shaped lcharges of explosive in proper position for firing to perforate the casing.

Fig. 8 is a vertical cross-sectional view of the gun of Figs. 6 and 7 after the charges of explosive have been red, the parts of the carriage being in such position that they can be retrieved from the well through the tubing.

Referring to the drawing in detail, and rst to the embodiment of the invention shown in Figs. 1 to 5, inclusive, it Will be seen that an oil well casing is there shown at I2. A tubing I3 is positioned in the Iwell with its lower end or openings I8 to permit bullets to. be red therethrough.

The gun barrels Il are of a length greater than the diameter of the tubing I3 and only slightly less than the diameter of the casing' I2. In .or-

der for them to be lowered into the well through the tubing, it is necessary that they be-held approximately in a vertical position as shown in Fig. 1. After the carriage has passed'outof the bottom of the tubing, the barrels I'I are to be rotated'to the horizontal-'position as shown in Fig. 2. The carriage Ie can then be raised and lowered by the cable and the guns i'lred individually at diiierent depths, or all ofthe guns may be red at the same time, or nearly so, in accordance with well known perforating technique.

If the guns are of the type which shoot bullets, each barrel I'I may be loaded at v'both ends with the explosive charge in the center, as taught in the patent to Minis No. 1,582,184, with the result that bull-ets 2d are red into the casing I2 vand surrounding earth formation 2i in both directions. With such an arrangement, there is little strain on the supporting structure, because the reactive firing forces balance out.v However, it is within the purview of the inventionto load each barrel I'I with only one bullet so as to increase the eiective gun barrel length and secure greater penetration and that is the type of arrangement illustrated in Fig. 5. l

After the bullets have been red, the arrangement is `such that the barrels Il may :be rotated back into approximately a vertical position as shown in Fig. 3, so that they can be pulled back up through the tubing I3 to remove them from the well.

The sequence of steps of Irotation. are illustrated in Figs. 1, 2 and 3 and they are carried out automatically due to the construction of the device. When being lowered down through the tubing I3. as shown in Fig. 1, the barrels are held approximately in vertical position Iby the tubing I3 itself. This is due to the construction of the `carriage le which is split longitudinally throughout its length. The barrels I'I are individually connected to bothr semi-cylindrical halves by the pivot pins I5 and the cable I5 is connected only to one half cf the carriage I4 so that the whole constitutes a parallel linkage mechanism, the barrels I'I themselves serving. as the bars linking the two halvesV of the carriage together. Thus the device may be run into the well with vthe two part-s of the `carriage I4 in the nested position shown in Fig. l, and after the device has passed out of the` lower end of the tubing the parts may separate into the extended position shown in Fig. 2. While in the running-in position, the barrels I'I are not quite Vertical with respect to the-center-line of the carriage I4 so that gravity tends to yrotate them into a horizontal position, but so long asv the gun is within the tubing they cannot be so rotated, because the carriage I4 is connedbythetubingit.

As soon as the carriage I4 is brought to apoint beneath the lower end of the tubing I3, gravity acts so that the parts of the carriage and the barrels I1 swing into the position shown in Fig. 2. This is the firing position of the gun.

If the barrels Il are each loaded with only one bulletA 2B, Ythey may be alternately directed, as illustrated, so. that one. fires to the left and the next to the right to stagger the perforations in the casing I2.

When the carriage and barrels take the ring position showny in Fig. 2, some means must be provided for holding them temporarily in that position While they iire. To this end, a profleeting..retainerA 22,- may be provided on the interior. ortho-carriage it which come into engagement. with one, of the barrels Il, as shown 'in' Fig. 2'. "As shown in Fig. 5, this particular barrel-'may have its right hand pivot pins It in a slot 23 in the carriage if?. and its right hand pivot pins it in-a slot- :i3/Hin said carriage.

Hence` .when this barrel is hired, the reaction causes it to kick to the right and 'shear the retainer 22. Gravity then-acts to swing the parts on down to the position shown in Fig. 3, so that they can be retrieved through the tubing.

if each of the barrels l? is loaded with two bullets which are discharged in opposite directions, as mentioned above, the particular barrel El which-is associated with theretainer 2i may be so loaded as to create a reaction in the desired direction to shear the retainer 22, as by imparting a greater driving force to the leit hand bullet than to the right hand bullet when the assembly is in the position shown in 2.

The apparatus of Figs. 6, '2, and '8 is somewhat similar to` that o Figs. lv to-, inclusive and functions Iin a similar manner, except that the casing perfor-ating guns consist of shaped charges oi explosive instead .of barrels iorshooting bullets, and utilize jet action. Since these shaped charges disintegrate-upon being there is nothing to retrieve from the `Jell except the `carriage. The parts which are the sai .e as those in Figs. 1 to 5 are similarly designated.

The shaped charges of explosive are shown at 2d. rihese charges are individually attached to the interior of the two halves of the carriage Iii. They remain in horizontal position no matter how the two halves of the carriage move with respect toeach other but they are nested together, as shown i1i.Fig. 6 when being lowered throughthe tubing I3. To provide the desired parallel linkage mechanism, bars i5 are pivoted by pins 2S to the two halves of, the carriage M. When the carriage comes out of the iower end of the tubing i3, the two halves separate radially and bring the shaped charges 2e intothe proper lstand-oit position with respect to their target, the casing I2. t will be observed that the firing position vof Fig. '7 is such that the bars .25, are not exactlyfhorizontal, the pins on the left being slightly lower than those on the right. The two haives-of the-carriage I4 are held in this position, until thecharges are iired, by a temporary retainer or shear pin 2.- When the charges are iired, due to theY offset position oi the pins 25, the reaction force shears the-pin 2 and permits the two halves ot .the carriage to take the retrieV-ing.- position shown in Fig.4 8. f

The firing mechanism and circuits, ior the guns herein illustrated and described have not been set forth for the reason that they may be conventional. They form no part Ofi the present invention. It will be understoodthat the-iring may be controlled from the surface of the ground through a conductor in the cable l5. It is also possible to cause the gun to fire upon the parts moving to the positions shown in Figs. 2 or '7, utilizing the iiring systems of the applications of Earl Babcock or William E. Kanady, Serial Nos. 184,166 and 184,157, iled on even date herewith. The invention is capable of use without the cable l5 if means is provided for securing the upper part of the right hand part or" the carrier d to the bottom of the tubing I3 so that the left hand part can swing down.

t is to be understood therefore that various changes may be made without departing from the spirit of the invention or the scope of the annexed claims.

I claim:

l. A device for perforating casing in an oil well below tubing suspended within said casing comprising an elongated gun carriage split longitudinally throughout its length to divide it into two parts, gun barrels pivoted to the two parts or" said carriage and forming therewith a parallel linkage mechanism, a retainer for holding said parts temporarily in an extended position and a means for shearing said retainer which utilizes the reaction force of one of said barrels when it is fired, whereby said carriage may be held with the two parts thereof in nested position by the tubing through which it is lowered into the well, separate, under the inuence of gravity, into an extended position after it has passed out of the lower end of the tubing and then fall into a retrieving position when said retainer is sheared.

2. A device for perforating casing in an oil well below tubing suspended within said casing comprising an elongated carriage split longitudinally throughout its length to divide it into two parts, bars pivoted to the two parts of said carriage and forming therewith a parallel linkage mechanism, shaped charges of explosive each of which is individually secured to the wall of said carriage, a retainer for holding said parts temporarily in an extended position and means for shearing said retainer which utilizes the reaction forces set up in the carriage when the charges are fired, whereby said carriage may be held with the two parts thereof in nested position by the tubing through which it is lowered into the well, separate, under the influence of gravity, into an extended position after it has passed out of the lower end of the tubing and then fall into a retrieving position when said retainer is sheared.

3. A device for perforating casing in an oil well below tubing suspended Within said casing comprising an elongated carriage split longitudinally throughout its length to divide it into two parts, bars pivoted to the two parts of said carriage and forming therewith a parallel linkage mechanism, explosive means disposed within the carriage for perforating the casing, a retainer for holding said parts temporarily in an extended position and means for shearing said retainer which utilizes the reaction force of said explosive means when it is fired, whereby said carriage may be held with the two parts thereof in nested position by the tubing through which is is lowered into the well, separate under the inuence of gravity into an extended position after it has passed out of the lower end of the tubing and then fall into a retrieving position when said retainer is sheared.

174,459 Great Britain Feb. 1, 1922 

